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Finding the double sunsets: close binary stars, large spectroscopic surveys

Dr. Carles Badenes
University of Pittsburgh / ICCUB

May 3rd, 2018


I will discuss our present knowledge of the statistics of stellar multiplicity (the multiplicity fraction and the distribution of periods, mass ratios, and eccentricities), and the implications for stellar evolution, in particular for Type Ia Supernovae (SN Ia). I will describe how multi-epoch radial velocity measurements from large spectroscopic surveys can open a new observational window on stellar multiplicity, and present two case studies: white dwarfs in SDSS/SEGUE and the ESO SPY survey, and main sequence stars and red giants in SDSS/APOGEE. For the white dwarfs, we can measure their merger rate and evaluate their viability as Type Ia SN progenitors. For the main sequence stars and red giants, we can explore the interplay between stellar evolution and stellar multiplicity, evaluate the rate of stellar mergers, and uncover a strong dependence of the multiplicity fraction with metallicity.